[PATCH v6 05/10] drm: Read DP branch device id

[Jim Bride]

On Wed, Jul 06, 2016 at 02:04:49PM +0300, Mika Kahola wrote:
> Read DisplayPort branch device id string.

Reviewed-by: Jim Bride <jim.bride at linux.intel.com>

> 
> Signed-off-by: Mika Kahola <mika.kahola at intel.com>
> ---
>  drivers/gpu/drm/drm_dp_helper.c | 12 ++++++++++++
>  include/drm/drm_dp_helper.h     |  2 ++
>  2 files changed, 14 insertions(+)
> 
> diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c
> index 95d624a..4003464 100644
> --- a/drivers/gpu/drm/drm_dp_helper.c
> +++ b/drivers/gpu/drm/drm_dp_helper.c
> @@ -513,6 +513,18 @@ int drm_dp_downstream_max_bpc(const u8 dpcd[DP_RECEIVER_CAP_SIZE],
>  }
>  EXPORT_SYMBOL(drm_dp_downstream_max_bpc);
>  
> +/**
> + * drm_dp_downstream_id() - identify branch device
> + * @aux: DisplayPort AUX channel
> + *
> + * Returns branch device id on success or NULL on failure
> + */
> +int drm_dp_downstream_id(struct drm_dp_aux *aux, char id[6])
> +{
> +	return drm_dp_dpcd_read(aux, DP_BRANCH_ID, id, 6);
> +}
> +EXPORT_SYMBOL(drm_dp_downstream_id);
> +
>  /*
>   * I2C-over-AUX implementation
>   */
> diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h
> index 47ae8ed..8264d54 100644
> --- a/include/drm/drm_dp_helper.h
> +++ b/include/drm/drm_dp_helper.h
> @@ -445,6 +445,7 @@
>  #define DP_SOURCE_OUI			    0x300
>  #define DP_SINK_OUI			    0x400
>  #define DP_BRANCH_OUI			    0x500
> +#define DP_BRANCH_ID                        0x503
>  
>  #define DP_SET_POWER                        0x600
>  # define DP_SET_POWER_D0                    0x1
> @@ -810,6 +811,7 @@ int drm_dp_downstream_max_clock(const u8 dpcd[DP_RECEIVER_CAP_SIZE],
>  				const u8 port_cap[4]);
>  int drm_dp_downstream_max_bpc(const u8 dpcd[DP_RECEIVER_CAP_SIZE],
>  			      const u8 port_cap[4]);
> +int drm_dp_downstream_id(struct drm_dp_aux *aux, char id[6]);
>  
>  void drm_dp_aux_init(struct drm_dp_aux *aux);
>  int drm_dp_aux_register(struct drm_dp_aux *aux);
> -- 
> 1.9.1